Setting up reverse proxy server

I need help to set up a reverse proxy server that can proxy on port 80 a custom application on localhost port 9090.

Even though I have added an external application to the virtual host, nothing is happening, so it's clear I am missing at least a step. Is there any full documentation about setting up a reverse proxy server on LiteSpeed, with instructions regarding rewrite, external apps, etc.?

LiteSpeed Web Server can be used as a transparent reverse proxy server running in front of any web server or application server that supports HTTP protocol, to help improve the scalability, performance and security of the whole system.
Please set up in the WebAdmin console according to the following steps:
Define an External Application with Type Web Server. Set Address to the IP address and port used by the backend web server.
Two choices:
Define a Proxy Context with Web Server set to the External Application just defined.
Define a Script Handler with Type Web Server, and Handler Name set to the External Application just defined.

If customer application is setup as name based vhost(need host header matches with server name), proxy request "Host" header needs to be modified in rewrite rule. Here is how:

say web site domain name is "www.example.com", it proxy request to backend, backend is defined as a web server with name "node1", it requires domain name to be "node1.example.com", the rewrite rule (web admin console->Configuration->Virtual Hosts->www.example.com->Rewrite) should be
^/(.*)$ http://node1/$1 [P,E=Proxy-Host:node1.example.com]

Thank you!
I found a third solution that I will document a bit later.
But now I have an additional issue. Is it possible to get the proxy password protected?
I tried to emulate the password protection found in the example but that doesn't work since it wants the proxied app to be password protected.